1. An information processing device, comprising: computer storage for storing information about components and subcomponents of first and second system models, each of the first and second system models having a plurality of subcomponents; at least one CPU programmed to operate as: (a) a determination unit connected to the computer storage for determining the correspondence between components of the first and second system models as a function of: (i) a plurality of first correspondence values, each first correspondence value indicating the similarity between a respective subcomponent of the first system model and a respective subcomponent of the second system model; and (ii) a plurality of second correspondence values, each second correspondence value indicating the similarity between a respective combination of subcomponents of the first system model and a respective combination of subcomponents of the second system model; the determination storage unit storing those of the first and second correspondence values which are greater than a predetermined threshold in a correspondence table; and (b) a calculation unit which generates a similarity value indicating the similarity of the first and second system models as a function of the first and second correspondence values stored in the correspondence table.