The G2 development and deployment environment

G2 is an object-oriented development and deployment environment, combining rule-based and procedural reasoning, user interface graphics, database interface capabilities, dynamic simulation, and real-time execution in a single package. The applications of G2 typically have large knowledge bases, with tens of thousands of objects, and generally real-time execution is required. The online installations span the process industries, discrete manufacturing, aerospace, telecommunications, electric utilities, and others. Primarily these installations have been implemented directly by plant engineers, who have defined the knowledge contained in the applications using G2´s structured natural language and active-object graphics. The design of G2 is described