Abstract
System identification of the thermal diffusivity for actual structures is possible only by an approximated method. Using the approximated, it is necessary to consider its conditions and accuracy. In the last paper, conditions and accuracy for the system identification of thermal diffusivity were discussed by the finite differential method and the cardinal spline method. In this paper, the author presents new identical equations using the application of cardinal spline method. The identical equation using the cardinal spline method can be exchanged by the integral equation. Thus, new identical equations can be presented by the approximated numerical integral of Newton-Cotes formula, and of the cubic spline function which uses the natural cubic spline, P-spline, and divided differences as the end conditions.
