Demon concepts in an active CIM knowledge base

Demons are parts of procedure code which are activated automatically by access to data in a knowledge base. A demon concept is presented which is built in an object-oriented knowledge base. The knowledge base is founded on the principles of object-oriented programming and frames and is used as an information tool for autonomous robots and machines in a production environment. It is shown how demons are integrated in this knowledge base and how demons can be used as a tool for type checking based on a special type concept. It is also shown that demons are useful in checking and maintaining the integrity of the knowledge base. How demons can be used to make the knowledge base active is discussed. This means the knowledge base can send information actively to interested processes. An example is given to demonstrate how the active knowledge base can be integrated in a CIM application