ABSTRACT
Open and closed user systems (e.g., statistical packages, optimization packages, numerical algorithm libraries) are widely used in industrial and scientific development environments and represent an enormous body of very complex and valuable knowledge that is becoming increasingly difficult to access. End users to these systems have to cope simultaneously with the intricacies of the software and with the increasing complexity of the application domain problems. For these systems, knowledge-based front-ends (KBFEs) can provide co-operative assistance to end users, enabling them to use the systems successfully while preserving know-how in the libraries and packages and extending their working life.
