. . "using said baseline sample to produce a new estimate Qi of said parameter Q at said time ti; and averaging Qi with said parameter's averaged estimate i???1 at the prior measurement time ti???1 to produce a value i of at time ti according to: ??? Q ??? i = N - 1 N ??? ( b ??? ??? Q ??? ( i - 1 ) ) + Q i N , where N is a constant and b corrects for its time variation between times ti a" . .