HR: 1340h
AN: H23B-1310    [Abstracts]
TI: Confidence Region Estimation for Groundwater Parameter Identification Problems
AU: * Vugrin, K W
EM: kwvugri@sandia.gov
AF: Sandia National Laboratories Carlsbad Programs Group Performance Assessment and Decision Analysis Department, 4100 National Parks Highway, Carlsbad, NM 88220, United States
AU: Swiler, L P
EM: lpswile@sandia.gov
AF: Sandia National Laboratories Optimization and Uncertainty Estimation Department, P.O. Box 5800, MS 0370, Albuquerque, NM 87187, United States
AU: Roberts, R M
EM: rmrober@sandia.gov
AF: Sandia National Laboratories Carlsbad Programs Group Repository Performance Department, 4100 National Parks Highway, Carlsbad, NM 88220, United States
AB: This presentation focuses on different methods to generate confidence regions for nonlinear parameter identification problems. Three methods for confidence region estimation are considered: a linear approximation method, an F--test method, and a Log--Likelihood method. Each of these methods are applied to three case studies. One case study is a problem with synthetic data, and the other two case studies identify hydraulic parameters in groundwater flow problems based on experimental well--test results. The confidence regions for each case study are analyzed and compared. Each of the three methods produce similar and reasonable confidence regions for the case study using synthetic data. The linear approximation method grossly overestimates the confidence region for the first groundwater parameter identification case study. The F--test and Log--Likelihood methods result in similar reasonable regions for this test case. For the second groundwater parameter identification case study, the linear approximation method produces a confidence region of reasonable size. In this test case, the F--test and Log--Likelihood methods generate disjoint confidence regions of reasonable size. The differing results, capabilities, and drawbacks of all three methods are discussed. Sandia is a multi program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04- 94AL85000. This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S Department of Energy.
DE: 1829 Groundwater hydrology
DE: 1847 Modeling
DE: 1849 Numerical approximations and analysis
DE: 1873 Uncertainty assessment (3275)
SC: Hydrology [H]
MN: 2007 Fall Meeting