Starting a Knowledge Engineering Project: A Step-By-Step Approach

Getting started on a new knowledge engineering project is a difficult and challenging task, even for those who have done it before. For those who haven’t, the task can often prove impossible. One reason is that the requirementsoriented methods and intuitions learned in the development of other types of software do not carry over well to the knowledge engineering task. Another reason is that methodologies for developing expert systems by extracting, representing, and manipulating an expert’s knowledge have been slow in coming. At Tektronix, we have been using a step-by-step approach to prototyping expert systems for over two years now. The primary features of this approach are that it gives software engineers who do not know knowledge engineering an easy place to start, and that it proceeds in a step-by-step fashion from initiation to implementation without inducing conceptual bottlenecks into the development process. This methodology has helped us collect the knowledge necessary to implement several prototype knowledge-based systems, including a troubleshooting assistant for the Tektronix FG-502 function generator and an operator’s assistant for a wave solder machine. One fundamental assumption we make is that knowledge is more valuable than inference strategies. Often a company may have only one chance to acquire the knowledge, but can work on it later at leisure. A second assumption is that a knowledge engineering project must provide adequate documentation of its progress. At any stage in the process, knowledge engineers must be able to show some fruits of their labor.