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                                                                                Fs
                      "                                                         Fc
                                                                                Fm
                                                       1st
                                                       2nd
                                                       3rd
                            (a) Navigation task               50    100   150   200   250
                                                                       step
                                                                 (c) Selected feature extractors
                    ftepO







                            (b) Resultant behavior               (d) Selected subsets of instance
                                     Figure 3: Task and experimental results

               effective  feature extractors.

               To verify the subset of instances, we performed the same experiment except for the procedure to select
               the  subsets.  In this  experiment,  the robot  always  selected  all instances.  In the result,  the average
               number of selected  feature  extractors per step is 1.97, which  is larger than the result of Figure 3. This
               means  that  the robot  spent  much  more  time  for  action  decision  at  each  step.  Hence,  the  robot
               effectively  decides the action using a portion of the instances.


               CONCLUSION
               This paper has proposed a method in which a robot learns to select image feature  extractors  generated
               by  itself  according  to a task-relevant  criterion.  A portion  of supervised  data  which  gives  the local
               information  of the task  makes  the selection  of  feature  extractors  more  effective.  In the proposed
               method, a robot can accomplish  more complicated  tasks  using multiple  feature  extractors. Our future
               work is to verify the extent of effectiveness  of the proposed method.

               References

                 McCallum, A. (1996). Learning to Use Selective Attention and Short-Term Memory in Sequential
                 Tasks. Proceedings of International Conference on Simulation of Adaptive Behavior, 315-324.

                 Minato,  T. and Asada,  M. (2003).  Towards  Selective  Attention:  Generating  Image  Features by
                 Learning a Visuo-Motor Map. Robotics and Autonomous Systems 45, 211-221.

                 Mitsunaga,  N.  and Asada,  M.  (2000).  Observation  Strategy  for  Decision  Making  based  on
                 Information  Criterion. Proceedings of International Conference on Intelligent Robots and Systems,
                  1038-1043.

                 Vlassis, N., Bunschoten, R., and Krose, B. (2001). Learning  Task-Relevant  Features  from  Robot
                 Data. Proceedings of International Conference on Robotics and Automation, 499-504.
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