Nicola Beume Holger Danielsiek Christian Eichhorn Boris Naujoks Mike Preuss Klaus Stiller Simon Wessing Measuring flow as concept for detecting game fun in the Pac-Man game. 3448-3455 2008 IEEE Congress on Evolutionary Computation http://dx.doi.org/10.1109/CEC.2008.4631264 conf/cec/2008 db/conf/cec/cec2008.html#BeumeDENPSW08