Longitudinal datasets measured repeatedly over time from individual subjects, arise in many biomedical, psychological, social, and other studies. Such multivariate time-series are often high-dimensional and contain missing values. A common approach to analyse this kind of data is to learn a low-dimensional representation using variational autoencoders (VAEs). However, standard VAEs assume that the learned representations are i.i.d., and fail to capture the correlations between the data samples. We propose a novel deep generative model, Longitudinal VAE (L-VAE), that uses a multi-output additive Gaussian process (GP) prior to extend the VAE's capability to learn structured low-dimensional representations imposed by auxiliary covariate information, and also derive a new divergence upper bound for such GPs. Our approach can simultaneously accommodate both time-varying shared and random effects, produce structured low-dimensional representations, disentangle effects of individual covariates or their interactions, and achieve highly accurate predictive performance. We compare our model against previous methods on synthetic and clinical datasets, and demonstrate the state-of-the-art performance in data imputation, reconstruction, and long-term prediction tasks.

该研究提出了一种称为长期VAE（L-VAE）的方法，通过使用多输出加性高斯过程（GP）先验来扩展VAE的能力，从而实现在辅助协变量信息的约束下学习结构化低维表示， 以及导出了一种新的KL离散度上界。该方法可以同时适应时间变化的共享和随机效应，产生结构化低维表示，剥离个体协变量或其相互作用的影响，以及实现高度准确的预测性能。

纵向变分自编码器