Research
Scientific Machine Learning

This study presents a rigid-deformation decomposition AI framework for 3D spatio-temporal prediction of vehicle collision dynamics. Conventional implicit neural representations struggle to capture high-frequency deformation modes in crash simulations. We address this by decoupling global rigid-body motion from local structural deformation through two scale-specific networks (RigidNet and DeformationNet), achieving a 29.8% reduction in rigid-body motion error, a 17.2% reduction in total interpolation error, and a 46.6% reduction in angular extrapolation error compared to undecomposed baselines. The framework recovers 92% of the directional correlation and 96% of the spatial deformation localization accuracy relative to an oracle upper bound, enabling physically consistent predictions for nonlinear collision dynamics.
Reference:
- Kim S, Seo M, Yang S, Kang N (2025) Rigid-Deformation Decomposition AI Framework for 3D Spatio-Temporal Prediction of Vehicle Collision Dynamics. arXiv preprint arXiv:2503.19712. https://arxiv.org/abs/2503.19712
Try the live demo of vehicle collision simulation on the project page.
Optimization Algorithm

This study introduces the Projected Variable Three-Term Conjugate Gradient (PVTTCG) algorithm, designed to overcome the trade-off between fast convergence and strong generalization in deep neural network training. By stabilizing the optimization path through geometric projection, PVTTCG consistently improves generalization performance across benchmarks and real-world applications such as vehicle crash prediction.
Reference:
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Kim S, Kim H*, Kang N, Lee TH* (2025) Projected variable three-term conjugate gradient algorithm for enhancing generalization performance in deep neural network training. Neurocomputing, 131568. https://doi.org/10.1016/j.neucom.2025.131568
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Kim H, Wang C, Byun H, Hu W*, Kim S, Jiao Q, Lee TH* (2023) Variable three-term conjugate gradient method for training artificial neural networks. Neural Networks 159:125โ136. https://doi.org/10.1016/j.neunet.2022.12.001