Title:

When the Equations Outnumber the Unknowns

A civil engineer’s treasure hunt in the world of inverse problems

Ertugrul Taciroglu

Professor

Civil & Environmental Engineering Department

University of California, Los Angeles, USA

Time: 2014/11/23/ 10:00-11:30

Venue: Civil Engineering B504    Chair: Zheng Lu, Associate Professor

Outline :

Every problem being solved in natural sciences and engineering is an inverse problem, wherein the nature of Nature is first probed with experiments that yield input output data; then these data are used to construct a parametric model. Data pairs outnumber the model parameters and hence approximations have to be made. Often the solution is not unique, which makes this a far more challenging problem than its counterpart, the forward problem. A generic inverse problem entails an objective function that quantifies the discrepancy between behavior predicted by a forward model and behavior that is directly measured. If a parametric forward model is available, the solution is typically sought through a constrained minimization of the objective function—the optimal values of the model parameters produce the best model predictions. Modeling and measurement errors, the spatial and temporal sparseness of measurements, and computational issues often complicate this process. This presentation will provide a brief overview of inverse problems, and present examples of model validation for seismic analysis, structural health monitoring, shape optimization/ identification, and target localization. The common theme in all these inverse problems will be the underlying forward problem, which is elastodynamics.

About the Speaker :

Ertugrul Taciroglu earned a B.S. degree in 1993 from Istanbul Technical University, and M.S. and Ph.D. degrees from the University of Illinois at Urbana-Champaign (UIUC) in 1995, and 1998, respectively. After a stint at the Center for Simulation of Advanced Rockets (UIUC) as a postdoctoral research associate, he joined the Civil & Environmental Engineering Department at UCLA in 2001. Dr. Taciroglu is the 2006 recipient of a U.S. National Science Foundation CAREER award, and the 2011 Walter Huber Prize of the American Society of Civil Engineers (ASCE). He serves in various technical committees of the American Society of Civil Engineers (ASCE). He is the Managing Editor of the ASCE Journal of Structural Engineering, and an Associate Editor of the ASCE Journal of Engineering Mechanics and EERI Earthquake Spectra.

All interested are welcome!