Soft Computing Models in Industrial and Environmental Applications, 6th International Conference SOCO 2011 - Kacprzyk, Janusz; Corchado, Emilio; Hassanien, Aboul Ella; Sedano, Javier; Snasel, Vaclav; Calvo, José Luis; Slezak, Dominik; Snasael, Vaclav (Springer Berlin Heidelberg, 2011)