A computer based modelling system includes a computer processor and a memory for storing a model database. A set of primitives is stored in the database. An interface coupled to the computer processor enables a user to input, retrieve and manipulate data within the database. A high level user of the...http://www.google.de/patents/US5019961?utm_source=gb-gplus-sharePatent US5019961 - Computer apparatus and method for logical modelling
