I made a lot of research about the way unary sig are compute in ProM during a several days. So I found this paper how explain Fuzzy mining: http://alexandria.tue.nl/extra2/200911996.pdf
The problem is that I didn't find the truth formula they use in ProM to make for example a cluster in Fuzzy mining. And it will be very helpfull if someone knows how to compute the sig in ProM.
By the way, if someone can explain to me how they normalize the utility function in Fig. 7.15. of the paper in the link above.