A computer-implemented method for use in simulating dynamic behavior of complex engineering systems comprised of several subsystems includes computing a Jacobian matrix based on output derivatives, wherein the output derivatives are based on corresponding state variable derivatives related to corresponding first input variables for each of a plurality of subsystems. In addition, a noise figure-measuring device 10 calculates the number of channels of WDM light and signal light wavelengths of the respective channels based on the P1 or P2, and performs analysis to calculate a noise figure NF and the like of an appointed wavelength range around the center of each wavelength thus calculated. The external charger can automatically detect which of the plurality of types of accessory charging coils is connected, and can adjust its operation accordingly.