Title: Obtaining Semantics in Bayesian Network Inference
Speaker: Cory Butz
Date:
Time: 3:30 pm
Place: Thorvaldson 105
Abstract:
Variable Elimination (VE), proposed by Zhang and Poole, is a standard algorithm for performing exact inference in discrete Bayesian networks. VE starts and ends with clear semantics, yet the intermediate factors constructed by VE are seen as not having semantics. In this seminar, we give an algorithm, called Semantics in Inference (SI) that denotes the semantics of every intermediate factor constructed by VE. We show that SI is correct in nearly every instance of Bayesian network inference. SI provides a better understanding of the theoretical foundation of Bayesian networks and can be used for improved clarity, as shown via an examination of Bayesian network literature. This work is also interesting in that it reveals that d-separation plays a much larger role in inference than the literature suggests.
Biography:
Cory J. Butz received his Ph.D. degree in computer science from the University of Regina, Regina, SK, Canada, in 2000. He then joined the School of Information Technology and Engineering at the University of Ottawa, Ottawa, ON, Canada, as an Assistant Professor. In 2001, he returned to the Department of Computer Science at the University of Regina, where he currently holds the rank of Professor. His research findings on Bayesian networks have drawn invitations to visit Google Inc., USA and the University of Cambridge, UK.