Using the system-model-operator metaphor for knowledge acquisition

The system-model-operator framework, which provides a unifying perspective for the ways that expert systems represent, organize, and apply knowledge, is discussed. With this framework, it is possible to reuse domain-general knowledge and chart the knowledge-acquisition effort needed to extend task-specific shells to other domains. The concept is illustrated in the medical-diagnosis context of Heracles-DX, the diagnosis shell developed from Neomycin. In particular, Topo, an expert system for configuration that was developed using the Heracles shell, is described.<>