Title page for ETD etd-12022002-111205


Type of Document Master's Thesis
Author Satterlee, Sarah Melissa
Author's Email Address smsatt@cs.com, sarahs@vt.edu
URN etd-12022002-111205
Title Evolution of the southern pine beetle legacy simulation model "SPBMODEL" using genetic algorithms.
Degree Master of Science
Department Entomology
Advisory Committee
Advisor Name Title
Stone, Nicholas D. Committee Chair
Brewster, Carlyle C. Committee Member
Salom, Scott M. Committee Member
Stephen, Frederick M. Committee Member
Keywords
  • southern pine beetle
  • genetic algorithms
  • model
  • simulation
Date of Defense 2002-10-10
Availability unrestricted
Abstract
SPBMODEL, a legacy southern pine beetle (SPB) simulation model, was translated into a new JavaTM model called Javahog. The Javahog output was verified to be essentially identical to SPBMODEL output by means of standard and paired t-tests. Javahog was placed online and is currently accessible via a servlet.

Genetic algorithms (GAs) were applied to the Javahog model. GAs are a type of optimization heuristic that operate as an analog to evolution. GAs "evolve" a very good solution to a complex problem. In this case, GAs were intended to evolve a very good version of SPBMODEL. GAs were applied in part to improve upon the SPBMODEL design, and in part to demonstrate that GAs are effective tools for recalibrating legacy simulation models. Beyond simply recalibrating model parameters, the GA was used to select optimal functional forms for the development rates of each SPB life stage.

The GA evolved a model that performed better than SPBMODEL at predicting observed field data, according to a balanced fitness function and according to sums of squared errors. However, from a visual comparison of the output of both models versus observed field data, neither model achieved satisfactory performance.

Files
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  EvolvingSPBMODEL2.pdf 760.61 Kb 00:03:31 00:01:48 00:01:35 00:00:47 00:00:04

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