Monday, October 31, 2011

Matching landscapes

Georgios Pierris, one of my PhD students had a very good idea today. In combining SOMs and RL we are defining two landscapes, the SOM landscape and the reward landscape. It would be very interesting to see if it would be possible to use the SOM landscape to approximate the RL landscape and, thus, calculate utilities for unexplored areas of the RL landscape. It brings to mind Ulrich Nehmzow's work on sub-symbolic planning.
  • John Pisokas and Ulrich Nehmzow, Performance Comparison of Three Subsymbolic Action Planners for Mobile Robots, Robotics and Autonomous Systems, 51(1):55-67, 2005
Must develop this idea further...

Monday, October 17, 2011

Dimensions of RLSOM

At the Cognitive Robotics Research Centre at the University of Wales, Newport, we have been working on a reinforcement learning self-organizing map (RLSOM).
Without going into the details of the RLSOM algorithm, I'd liek to list some potential extensions:
  • From fixed length memory to primitives
  • STM Length and Learning Frequency
  • Representing space using decaying activation
  • Sparse representation of connections
  • One-shot and incremental learning
  • Pre-structuring hierarchies
  • Random connections across hierarchical levels