I don't know of SCEC and the site appears to be in Italian. I'm not sure what "much more near a DU" means. Is DU = UD?

I'm not sure I understand the point of the graph. Given the scale and resolution, I can not derive the functions behind them.

Do they say, create a linear amount of currency until you reach a total amount of X in year 13. (parabolic part of the rate graph)

Then create a parabolic amount of currency 5%? (linear part of the rate graph)

Yes to all !

I don't know SEL. Is that an abbreviation for "selection system"?

SEL (Système d'Echange Local) = LET (Local Exchange System)

The example LETS I described uses a zero initial starting balance. And it allows each participate to review the behavior of other participants and individually decide if they want to advance them credit in each particular transactional situation.

I understand but I'm not in favor of such a system.

For me money (and in specifically UD) is the solution to solve what I call the "time-space 3 producers problem"

At t=0 X want Vy (value produced by Y), Y want Vz, and Z want Vx, and for X Vz is no value, for Y Vx is no value, and for Z Vy is no value.

They can exchange in a circular way, and create money for that in equal proportion to each one to do it in a fair way.

At t X,Y and Z are died, but an economy remain (after many years of CONTINOUS transformation), it remains A,B,C exchanging Va, Vb, Vc, which are totally different values than Vx, Vy, Vz, which are considered by them as no value.

And so on, generations after generations.