publications

2026

1. AISTATS

   Spotlight

   

   Hellinger Multimodal Variational Autoencoders

   Huyen Vo and Isabel Valera

   In The 29th International Conference on Artificial Intelligence and Statistics, 2026

   Spotlight Presentation [2.5%]

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   Spotlight

   Multimodal variational autoencoders (VAEs) are widely used for weakly supervised generative learning with multiple modalities. Predominant methods aggregate unimodal inference distributions using either a product of experts (PoE), a mixture of experts (MoE), or their combinations to approximate the joint posterior. In this work, we revisit multimodal inference through the lens of probabilistic opinion pooling, an optimization-based approach. We start from Hölder pooling with α=0.5, which corresponds to the unique symmetric member of the α-divergence family, and derive a moment-matching approximation, termed Hellinger. We then leverage such an approximation to propose HELVAE, a multimodal VAE that avoids sub-sampling, yielding an efficient yet effective model that: (i) learns more expressive latent representations as additional modalities are observed; and (ii) empirically achieves better trade-offs between generative coherence and quality, outperforming state-of-the-art multimodal VAE models.

2022

1. NeurIPS

   

   Improving Neural Ordinary Differential Equations with Nesterov’s Accelerated Gradient Method

   Nghia Nguyen, Tan Minh Nguyen, Huyen Vo, and 2 more authors

   In Advances in Neural Information Processing Systems, 2022

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   We propose the Nesterov neural ordinary differential equations (NesterovNODEs), whose layers solve the second-order ordinary differential equations (ODEs) limit of Nesterov’s accelerated gradient (NAG) method, and a generalization called GNesterovNODEs. Taking the advantage of the convergence rate O(1/k^2) of the NAG scheme, GNesterovNODEs speed up training and inference by reducing the number of function evaluations (NFEs) needed to solve the ODEs. We also prove that the adjoint state of a GNesterovNODEs also satisfies a GNesterovNODEs, thus accelerating both forward and backward ODE solvers and allowing the model to be scaled up for large-scale tasks. We empirically corroborate the advantage of GNesterovNODEs on a wide range of practical applications, including point cloud separation, image classification, and sequence modeling. Compared to NODEs, GNesterovNODEs require a significantly smaller number of NFEs while achieving better accuracy across our experiments.