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Yuncherl Choi

Publications and source records attributed to Yuncherl Choi.

2 recordsLinked to original sources

Parameter Estimation and Adaptive Solution of the Leray-Burgers Equation Using Physics-Informed Neural Networks

In this paper, we employ the Physics-Informed Neural Network (PINN) to estimate the practical range of the characteristic wavelength parameter(referred to as the smoothing parameter) $α$ in the Leray-Burgers equation. The Leray-Burgers equation, a regularization of the inviscid Burgers equation, incorporates a Helmholtz filter with a characteristic wavelength $α$ to replace the usual convective velocity, inducing a regularized convective velocity. The filter bends the equation's characteristics slightly and makes them not intersect each other, leading to a global solution in time. By conducting computational experiments with various initial conditions, we determine the practical range of $α>0$ that closely approximates the solutions of the inviscid Burgers equation. Our findings indicate that the value of $α$ depends on the initial data, with the practical range of $α$ being between 0.01 and 0.05 for continuous initial profiles and between 0.01 and 0.03 for discontinuous initial profiles. The Leray-Burgers equation captures shock and rarefaction waves within the temporal domain for which training data exists. However, as the temporal domain extends beyond the training interval, data-driven forward computation demonstrates that the predictions generated by the PINN start to deviate from the exact solutions. This study also highlights the effectiveness and efficiency of the Leray-Burgers equation in real practical problems, specifically Traffic State Estimation.

physics.flu-dyn

A characterization of Cayley Hypersurface and Eastwood and Ezhov conjecture

Eastwood and Ezhov generalized the Cayley surface to the Cayley hypersurface in each dimension, proved some characteristic properties of the Cayley hypersurface and conjectured that a homogeneous hypersurface in affine space satisfying these properties must be the Cayley hypersurface. We will prove this conjecture when the domain bounded by a graph of a function defined on $\R^n$ is also homogeneous giving a characterization of Cayley hypersurface. The idea of the proof is to look at the problem of affine homogeneous hypersurfaces as that of left symmetric algebras with a Hessian type inner product. This method gives a new insight and powerful algebraic tools for the study of homogeneous affine hypersurfaces.

math.DG