Visiting Speaker: Tim Kovacs

ACCS Special Seminar


This week we have a special seminar linking in via a video conferencing to the ACCS Node at ADFA to hear Tim Kovacs who is a leader in the field of Learning Classifier Systems (LCS).

Place: Room 621, GP South (Building 78)
Time: Wednesday 30th November, 9:45 morning Tea. 10:00am seminar (Brisbane time)

Title:  "Strength or Accuracy? Credit assignment in Classifier Systems""
Presenter: Tim Kovacs
Department of Computer Science, Bristol University

http://www.cs.bris.ac.uk/~kovacs/author.directory/publications.html

Abstract
This talk reviews some work on the problem of crediting individual components of a complex adaptive system for their often subtle effects on the world. For example, in a game of chess, how did each move (and the reasoning behind it) contribute to the outcome? Application of adaptive methods, whether to classification or control tasks, requires effective approaches to this sort of credit assignment problem.

A fundamental approach is to evaluate components of solutions, rather than complete solutions, with the intention of simplifying the credit assignment problem. This is the approach taken by Michigan Learning Classifier Systems, which combine Evolutionary Algorithms, to generate solution components, and Reinforcement Learning methods to evaluate them.

Unfortunately, as will be outlined, serious complications arise from this attempt at simplification. Most significantly, it will be shown that both of the main approaches (strength-based and accuracy-based systems) have difficulties with certain tasks which the other type does not. The talk will also outline the causes of the main difficulties each type of system faces, the types of tasks which cause these ifficulties, and prospects for addressing them.




World-class basic and applied inter-disciplinary research on questions fundamental to understanding, designing and managing complex systems
2009 The ARC Centre for Complex Systems, Australia