Discriminative Training of Mixed Membership Models
Jun Zhu Department of Computer Science and Technology, State Key Laboratory of Intelligent Technology and Systems; Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing 100084, China
Eric P. Xing School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
Mixed membership models have shown great promise in analyzing genetics, text documents, and social network data. Unlike most existing likelihood-based approaches to learning mixed membership models, we present a discriminative training method based on the maximum margin principle to utilize supervising side information such as ratings or labels associated with documents to discover more predictive low-dimensional representations of the data. By using the linear expectation operator, we can derive efficient variational methods for posterior inference and parameter estimation. Empirical studies on the 20 Newsgroup dataset are provided. Our experimental results demonstrate qualitatively and quantitatively that the max-margin-based mixed membership model (topic model in particular for modeling text): 1) discovers sparse and highly discriminative topical representations; 2) achieves state-of-the-art prediction performance; and 3) is more efficient than existing supervised topic models.