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EFFICIENT LARGE SCALE TRANSIENT HEAT CONDUCTION ANALYSIS USING A PARALLELIZED BOUNDARY ELEMENT METHOD
Title
EFFICIENT LARGE SCALE TRANSIENT HEAT CONDUCTION ANALYSIS USING A PARALLELIZED BOUNDARY ELEMENT METHOD.
Creator
Erhart, Kevin, Divo, Eduardo, University of Central Florida
Abstract / Description
A parallel domain decomposition Laplace transform Boundary Element Method, BEM, algorithm for the solution of large-scale transient heat conduction problems will be developed. This is accomplished by building on previous work by the author and including several new additions (most note-worthy is the extension to 3-D) aimed at extending the scope and improving the efficiency of this technique for large-scale problems. A Laplace transform method is utilized to avoid time marching and a Proper...
Show moreA parallel domain decomposition Laplace transform Boundary Element Method, BEM, algorithm for the solution of large-scale transient heat conduction problems will be developed. This is accomplished by building on previous work by the author and including several new additions (most note-worthy is the extension to 3-D) aimed at extending the scope and improving the efficiency of this technique for large-scale problems. A Laplace transform method is utilized to avoid time marching and a Proper Orthogonal Decomposition, POD, interpolation scheme is used to improve the efficiency of the numerical Laplace inversion process. A detailed analysis of the Stehfest Transform (numerical Laplace inversion) is performed to help optimize the procedure for heat transfer problems. A domain decomposition process is described in detail and is used to significantly reduce the size of any single problem for the BEM, which greatly reduces the storage and computational burden of the BEM. The procedure is readily implemented in parallel and renders the BEM applicable to large-scale transient conduction problems on even modest computational platforms. A major benefit of the Laplace space approach described herein, is that it readily allows adaptation and integration of traditional BEM codes, as the resulting governing equations are time independent. This work includes the adaptation of two such traditional BEM codes for steady-state heat conduction, in both two and three dimensions. Verification and validation example problems are presented which show the accuracy and efficiency of the techniques. Additionally, comparisons to commercial Finite Volume Method results are shown to further prove the effectiveness.
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Date Issued
2006
Identifier
CFE0001291, ucf:46881
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001291
A DIRECT COMPENSATOR PROFILE OPTIMIZATION APPROACH FOR INTENSITY MODULATED RADIATION TREATMENT PLANNING
Title
A DIRECT COMPENSATOR PROFILE OPTIMIZATION APPROACH FOR INTENSITY MODULATED RADIATION TREATMENT PLANNING.
Creator
Erhart, Kevin, Divo, Eduardo, University of Central Florida
Abstract / Description
Radiation therapy accounts for treatment of over one million cancer patients each year in the United States alone, and its use will continue to grow rapidly in the coming years. Recently, many important advancements have been developed that greatly improve the outcomes and effectiveness of this treatment technique, the most notable being Intensity Modulated Radiation Therapy (IMRT). IMRT is a sophisticated treatment technique where the radiation dose is conformed to the tumor volume, thereby...
Show moreRadiation therapy accounts for treatment of over one million cancer patients each year in the United States alone, and its use will continue to grow rapidly in the coming years. Recently, many important advancements have been developed that greatly improve the outcomes and effectiveness of this treatment technique, the most notable being Intensity Modulated Radiation Therapy (IMRT). IMRT is a sophisticated treatment technique where the radiation dose is conformed to the tumor volume, thereby sparing nearby healthy tissue from excessive radiation dose. While IMRT is a valuable tool in the planning of radiation treatments, it is not without its difficulties. This research has created, developed, and tested an innovative approach to IMRT treatment planning, coined Direct Compensator Profile Optimization (DCPO), which is shown to eliminate many of the difficulties typically associated with IMRT planning and delivery using solid compensator based treatment. The major innovation of this technique is that it is a direct delivery parameter optimization approach which has adopted a parameterized surface representation using Non-Uniform Rational B-Splines (NURBs) to replace the conventional beamlet weight optimization approach. This new approach brings with it three key advantages: 1) a reduced number of parameters to optimize, reducing the difficulty of numerical optimization; 2) the ability to ensure complete equivalence of planned and actual manufactured compensators; and 3) direct inclusion of delivery device effects during planning with no performance penalties, eliminating the degrading fluence-to-delivery parameter conversion process. Detailed research into the affects of the DCPO approach on IMRT planning has been completed and a thorough analysis of the developments is provided herein. This research includes a complete description of the DCPO surface representation scheme, inverse planning process, as well as quantification of the manufacturing constraint control procedure. Results are presented which demonstrate the performance and innovation offered by this new approach and show that the resulting compensator shapes can be manufactured to nearly 100 percent of the designed shape.
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Date Issued
2009
Identifier
CFE0002800, ucf:48099
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002800