  This is a full-paper of the paper(Physica C341-348, 259(2000)) published
previously. The effective charge and the Coulomb energy are justified by means
of measurement. Theoretical calculations of the effective mass depending on
band filling are also given by Gutzwiller's variational calculations. On the
basis of the concept of measurement, the effective mass is an average of the
true effective mass in the Brinkman-Rice(BR) picture for metal phase and is the
effect of measurement. The true correlation strength (U/U_c=k_{BR}) in the BR
picture is evaluated as 0.92<k_{BR}<1 for YBCO. High-Tc superconductivity is
attributed to the true effective mass caused by the large k_{BR} value.
Furthermore, the validity of the BR picture is indirectly proved through the
extended BR picture.
