and the other already described influencing quantities and the output quantities namely the web strength f aw or respectively the quantity correlated with it for this purpose are stored for a plurality of winding processes in order to be able to train the neural network therewith since the output quantity is not measurable its determination is a problem therefore it is initially proposed to calculate this non measurable quantity f aw namely the web strength from known measurable quantities analogously the average layer thickness can be calculated from the radius increase and the number of layers according to fig2 there is a relationship between the web strength f aw the coil radius r aw and the number of layers of the wound paper according to the invention the web strength f aw r therefore can be reconstructed depending on the coil radius r in that for example the coil radius r aw is measured depending on the number of paper layers z fig2 also shows that there is a relationship between the web strength and the radial deformation of the paper which then has an effect on the coil radius dependent on the number of layers and the roll up coil hardness as well as on the average layer thickness for example three paper layers are already wound up in fig2 the web strengths f aw 1 f aw 2 f aw 3 are allocated to.