NPIA for fast computation of almost correct estimate of value sets of transfer functions

In this paper, we present how nonconvex polygon interval arithmetic (NPIA) are defined and implemented. NPIA is the arithmetic defined on the set of all polygons in the complex plane, and it is very useful to compute estimates of value sets of transfer functions including uncertain physical parameters in a reasonable computing time. If an expression of the transfer function corresponding to the totally decomposable tree-structured decomposition is given, the obtained estimate is included an /spl epsi/ neighborhood of the region enclosed by the outer boundary of the value set.