Olivier Pietquin editor Smaranda Muresan editor Vivian Chen editor Casey Kennington editor David Vandyke editor Nina Dethlefs editor Koji Inoue editor Erik Ekstedt editor Stefan Ultes editor 2020-07 Association for Computational Linguistics 1st virtual meeting text conference publication sigdial-2020-special https://aclanthology.org/2020.sigdial-1.0/