A Recurrent Markov State-Space Generative Model for Sequences

Abstract

While the Hidden Markov Model (HMM) is a versatile generative model of sequences capable of performing many exact inferences efficiently, it is not suited for capturing complex long-term structure in the data. Advanced state-space models based on Deep Neural Networks (DNN) overcome this limitation but cannot perform exact inferences. In this article, we present a new generative model for sequences that combines both aspects, the ability to perform exact inferences and the ability to model long-term structure, by augmenting the HMM with a deterministic, continuous state variable modeled through a Recurrent Neural Network. We empirically study the performance of the model on (i) synthetic data comparing it to the HMM, (ii) a supervised learning task in bioinformatics where it outperforms two DNN-based regressors and (iii) in the generative modeling of music where it outperforms many prominent DNN-based generative models.