User participation models in online forum and regularization methods for classifier combination
Speaker: Chun-hung Li (Assistant Professor at Hong Kong Baptist University)
In the first part of the talk, we will briefly go over our recent work
on the modeling of user participation in online discussion
forum. While topic detection and tracking based on document corpus has
gained significant advances in recent years, the analysis of online
discussion is often limited by its terseness. Using non-negative
matrix factorization, user participation models can be developed to
help us gain insights on the latent base topics of online discussions.
The second part of the talk covers regularization methods for
classifier combination. Majority voting in classifier combination
treats all base classifiers equally without considering their
performance differences. We will present a regularized classifier
combination strategy that maximize the entropy of probability weights
assigned to base classifiers subjected to the margin constraints of
the ensemble classifier.