Interval mathematics for knowledge-based computer aided design in magnetics

The use of interval mathematics in a knowledge-based system for electromagnetic device design is discussed. It is shown that, through interval propagation, the expert designer can observe the consequences of imposing interval bounds on parameters so that the nonexpert user can then receive advice regarding the legal range of design specifications. However, there are some problems in utilizing interval mathematics within a network of design equations exhibiting complex parameter dependencies. Constraint propagation methods involving single-valued quantities cannot be substituted directly. Interval techniques have proved to be valuable at various stages of the design process as a knowledge integrity tool and as an aid to end-users of the CAD (computer-aided design) system. The usage of these methods in electromagnetics is not restricted to expert systems, however. They may also find applications in low-level numerical algorithms for electromagnetics.<>