Bliek, A., Delft Univ of Technology, Delft, Netherlands
Honig, H.J., Delft Univ of Technology, Delft, Netherlands
Sommerhalder, R., Delft Univ of Technology, Delft, Netherlands

The DAG expert system is part of the Entity Model Manager (OEM manager) database system. The philosophy of the DAG system was to design a software package that would not only have the capabilities of a conventional expert system but that would also be able to diagnose multiple simultaneous faults based on non-monotonic reasoning techniques and Truth-Maintenance-System. These particular features of the software were based on the graph searching techniques. The end result was a prototype that performed better than the initial expectations.