Electrical Engineering and Computer Science

Distinguished Lecture

Uncertainty in an unknown world

Stuart Russell

Professor
University of California, Berkeley
 
Monday, October 10, 2005
4:30pm - 6:00pm
Chesebrough Auditorium

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About the Event

Recent advances in knowledge representation for probability models have allowed for uncertainty about the properties of objects and the relations that might hold among them. Such models, however, typically assume exact knowledge of which objects exist and of which object is which---that is, they assume *domain closure* and *unique names*. These assumptions greatly simplify the sample space for probability models, but are inappropriate for many real-world situations. This talk presents a formal language, BLOG, for defining probability models over worlds with unknown objects and in which several terms may refer to the same object. The language has a simple syntax based on first-order logic, combined with local probability functions for quantifying conditional dependencies. A key additional element is the *number* statement, which specifies a conditional distribution over the number of objects that satisfy a given property. Subject to certain acyclicity constraints, every BLOG model specifies a unique probability distribution over the full set of possible worlds for the first-order language. Furthermore, complete inference algorithms exist for a large fragment of the language. I will present several example models and discuss interesting issues arising from the treatment of evidence in such languages.

Biography

Professor Russell is the Director for the Center for Intelligent Systems.

Additional Information

Contact: J. Patterson

Phone: 4-8504

Email: jeannecp@umich.edu

Sponsor: CSE Division

Open to: Public