\(f_v^t(v)=k^t/c^t.(v^t/c^t)^(k^t-1).\exp(-(v^t/c^t)^(k^t-1))forc^t>1:k^t>0(4)\)
The parameter \((k^t)\) and the scale factor\((c^t)\)  in the time segment tm are calculated as follows: