Department of Mathematics and Statistics, University of Canterbury.
Ngin-Tee Koh received his doctorate from the University of Illinois at Urbana-Champaign in 2009. His thesis supervisor was Professor Aimo Hinkkanen.
For more details, here's a CV.
Note: Energy-minimal diffeomorphisms are also known as least squares conformal mappings in computer graphics. Their applications include automatic texture atlas generation and geometrically aware and self-configuring projectors.
If you've problems accessing the links below and would like a copy/preprint of any paper, just send me an email.
Abstract: The paper establishes the existence of homeomorphisms between two planar domains that minimize the Dirichlet energy. Specifically, among all homeomorphisms f : R -> R* between bounded doubly connected domains such that Mod (R) < Mod (R*) there exists, unique up to conformal authomorphisms of R, an energy-minimal diffeomorphism. No boundary conditions are imposed on f. Although any energy-minimal diffeomorphism is harmonic, our results underline the major difference between the existence of harmonic diffeomorphisms and the existence of the energy-minimal diffeomorphisms. The existence of globally invertible energy-minimal mappings is of primary pursuit in the mathematical models of nonlinear elasticity and is also of interest in computer graphics.
Abstract: In this article, we introduce some Tauberian-type conditions and prove variants of Hardy-Littlewood's high indices theorem for certain classes of series.
Abstract: A harmonic self-homeomorphism of a disk does not increase the area of any concentric disk.
Abstract: We prove a distortion theorem for conformal mappings whose images are quasidisks. As an application, we construct a quasiconformal reflection with bounded partial derivatives near the reflection boundary based on the Douady-Earle extension.
Abstract: We study a question posed by Anderson and Hinkkanen: what quasidisks are approximable? We show that a Jordan domain bounded by an analytic curve is an approximable quasidisk.
Abstract: We provide an integral estimate for the boundary values of a normalized quasiconformal self-mapping of the unit disk. Estimates are also given for the partial derivative of the Douady-Earle extension.
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Pictures of a Pacific Northwest journey (High speed connection required - if you've a slow connection, you may view the pictures here)