Minisymposia Abstracts

Speaker: Roland Potthast
University of Reading
Title: On Duality Relations between Reconstruction Methods in Inverse Scattering Theory
Abstract: TBA

Speaker: Olha Ivansyshyn
Technical University Darmstadt
Title: Inverse scattering for surface impedance from phase-less far field data
Abstract: TBA

Speaker: Xudong Chen
National University of Singapore
Title: Subspace-based Optimization Method in Solving Inverse Scattering Problems Involving Perfectly Electric Conductors
Abstract: TBA
Speaker: Hyeonbae Kang
Inha University
Title: Generalized polarization tensors and approximate cloaking
Abstract: TBA

Speaker: Weidong Zhu
University of Maryland, Baltimore County
Title: Detection of Damage in Structures Using Changes in Natural Frequencies
Abstract: A structural damage detection method that uses changes in natural frequencies to detect damage has advantages over conventional nondestructive tests in detecting various types of damage using minimum measurement data. Two major challenges associated with the applications of the vibration-based damage detection method to practical engineering structures are addressed: accurate modeling of test structures and the development of a robust inverse algorithm to detect damage, which are defined as the forward and inverse problems associated with the damage detection method, respectively. To resolve the forward problem, new physics-based finite element (FE) modeling techniques for fillets in thin-walled beams and bolted joints are developed, so that complex structures with thin-walled beams and/or bolted joints can be accurately modeled with a reasonable model size. To resolve the inverse problem, a robust iterative algorithm using a trust-region method, called the Levenberg-Marquardt (LM) method is developed to accurately detect the locations and extent of damage using a minimum number of measured natural frequencies. The LM method can ensure global convergence of the iterations in solving severely under-determined systems and deal with damage detection problems with relatively large modeling error and measurement noise. The vibration-based damage detection method developed is applied to various structures including lightning masts, a space frame structure and one of its components, and a pipeline. The locations and extent of damage can be successfully detected in experimental damage detection. In the numerical simulation where there are no modeling error and measurement noise, the exact locations and extent of damage can be detected.

Speaker: Jiguang Sun
Delaware State University
Title: Estimation of Dirichlet and Transmission Eigenvalues from near field Cauchy data
Abstract: TBA

Speaker: Gang Bao and Hai Zhang
Michigan State University
Title: Unique determination of bi-periodic polyhedron gratings by scattered electromagnetic waves
Abstract: TBA

Speaker: Yongzhi Steve Xu
University of Louisville
Title: Inverse obstacle scattering problems in an essentially stratified medium
Abstract: TBA

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