"Verification, Validation and Sensitivity Studies in Computational Biomechanics"
Abstract: The field of computational biomechanics has grown explosively over the last 10 years. For instance, subject-specific and patient-specific modeling techniques provide a valuable framework for studies ranging from the basic sciences to patient-specific surgical planning. This talk will discuss verification, validation and sensitivity studies in the context of the speaker's experience with applications in computational biomechanics. Verification refers to the process of determining whether or not a model can be used to represent the underlying principles of continuum mechanics with sufficient accuracy. Validation is the comparison of model predictions with experimental measurements. There is no way to completely verify or validate a model. This is analogous to the way that scientific theories cannot be proven but only dis-proven. However, once an exception is found, it invalidates that particular prediction or set of predictions under the conditions that were investigated. The investigator must pose specific hypotheses regarding model verification and validation, along with appropriately chosen tolerances, and then test these hypotheses. The underlying null hypothesis should be that the model does not reproduce the principles of mechanics or that the model does not predict experimental data. Repeated rejection of the null hypothesis for tests of descriptive and predictive capabilities provides confidence in the use of the model. Finally, sensitivity studies, which examine the sensitivity of model predictions to variations in inputs, are an extremely valuable addition to verification and validation, providing insight to the physics of the model and improving confidence in model predictions. These three techniques provide a powerful framework for developing and interpreting models in computational biomechanics, and insuring the acceptance of models as investigative tools.
Departments of Bioengineering and Orthopedics
Scientific Computing and Imaging Institute
University of Utah
http://hodad.sci.utah.edu/~weiss/mrl
Jeff Weiss is an Associate Professor of Bioengineering, an Adjunct Associate Professor of Orthopedics and a Faculty Member in the Scientific Computing and Imaging (SCI) Institute at the University of Utah. He grew up in Southern California and received the B.S. (1989) and M.S. (1990) degrees in Bioengineering from the University of California, San Diego. He completed his Ph.D. in Bioengineering at the University of Utah in 1994. Dr. Weiss received postdoctoral training in computational biomechanics as a finite element analyst working with the Applied Mechanics and Methods Development Groups at Lawrence Livermore National Laboratory.
Research in the Weiss Laboratories has historically focused on the biomechanics and healing of musculoskeletal soft tissues, in particular the ligaments of the knee. Over the past five years, the research focus has expanded considerably to include hard tissue as well as cardiovascular tissues including the heart, coronary arteries and smaller vessels involved in angiogenesis. A central theme of the approach to research is the use of multidisciplinary techniques. A primary strength continues to be the combination of both experimental and computational techniques, especially in the area of biomechanics, to address research questions that would be impossible to investigate using approaches from a single technical discipline. Major areas of research focus include subject-specific computational modeling of hip, knee and shoulder biomechanics, structure-function relationships in connective tissues, mechanical aspects of angiogenesis, and the direct integration of image data into biomechanical analyses.
Professor Weiss routinely serves on study section panels for the NIH and NSF and is currently an Associate Editor for the Journal of Biomechanical Engineering, the Journal of Applied Biomechanics and Computer Methods in Biomechanics and Biomedical Engineering. He is a regular reviewer for 15 additional international journals. Dr. Weiss has received a number of highly coveted awards, including the Taylor & Francis prize for outstanding innovation in computer methods in biomechanics & biomedical engineering, the ASME YC Fung Young Investigator Award in May 2002, a NSF CAREER Award in February 2002 and a Whitaker Foundation Research Grant in March 1995.