Model-free POMDP optimisation of tutoring systems with echo-state networks Lucie Daubigney author Matthieu Geist author Olivier Pietquin author 2013-08 text Proceedings of the SIGDIAL 2013 Conference Maxine Eskenazi editor Michael Strube editor Barbara Di Eugenio editor Jason D Williams editor Association for Computational Linguistics Metz, France conference publication daubigney-etal-2013-model https://aclanthology.org/W13-4014/ 2013-08 102 106