An improved system and method for network management is presented which facilitates better administration with a more intuitive reflection of the organizational structure with integrated security concerns by introducing novel strategies for grouping users of a network. or more at the time of thin film formation so as to provide the piezoelectric film, and a quick cooling is given from the thin film formation temperature at least to 450\xb0 C. Additionally, when a read-out voltage is applied between the ground terminal and the power source voltage terminal that are in connection with the source and drain regions, the MISFET is turned either on or off in correspondence to the state of the charge held in the floating gate electrode, and thus information within the floating gate electrode is read out.