CERC Technical Report Series

Research Note

CERC-TR-RN-91-013

Object-Oriented Knowledge Bases in Engineering Applications

M. Sobolewski

August 1991

ACKNOWLEDGEMENT: This effort has been sponsored by Defense Advance Research Projects Agency (DARPA), under contract No. MDA972-88-C-0047 for DARPA Initiative in Concurrent Engineering(DICE).

Concurrent Engineering Research Center
West Virginia University
Drawer 2000, Morgantown WV 26506

6 th Intrnationanl Conference on CAD/CAM Robotics & Factories of the Future London 19 -22 August 1991

Object-Oriented Knowledge Bases in Engineering Applications*

M. SOBOLEWSKI
Concurrent Engineering Research Center
West Virginia University, Morgantown 26506
E-Mail: [email protected]

Summary
An object-oriented knowledge-based system has been developed, using a new knowledge representation paradigm. Its high-level architecture includes a problem-solving engine, a user interface, and tools. Its low-level architecture is described by more than 50 different kinds of objects that are implemented in the system as Smalltalk classes. A procedural attachment mechanism, bidirectional data exchange between the inference engine and procedure calls are basic mechanisms used for object-oriented integration of declarative and procedural knowledge bases.

Introduction

A number of problems encountered in engineering design are not amenable to algorithmic solutions, for example finite elements methods and circuit simulators. These problems are often ill structured (the term ill-structured problems is used here to denote problems that do not have an explicit, clearly defined algorithmic solution). Experienced engineers deal with them using judgement and experience. Knowledge-based programming technology offers a methodology to tackle these ill-structured design problems. We have developed such a system called DICEtalk.

The DICEtalk knowledge-based system [7, 8] has been designed for engineers. The low-level architecture of the DICEtalk system is described by special kinds of objects that are implemented as more than 50 Smalltalk classes. The DICEtalk high-level architecture includes a problem-solving engine, a high-level user interface, and high-level tools. It features objectorientation (high-level structured programming) which provides procedural knowledge-based programming integrated with simplified English as declarative knowledge-based programming. The integration of both declarative and procedural knowledge bases is supported by an extended graphical user interface with access to several knowledge bases.